A wide range of medical treatments are known that utilize “endoluminal prostheses.” As used herein, endoluminal prostheses are intended to mean medical devices that are adapted for temporary or permanent implantation within a body lumen, including both naturally occurring and artificially made lumens. Examples of lumens in which endoluminal prostheses may be implanted include, without limitation: arteries, veins, gastrointestinal tract, biliary tract, urethra, trachea, hepatic and cerebral shunts, and fallopian tubes.
Stent prostheses are known for implantation within a body lumen for providing artificial radial support to the wall tissue that defines the body lumen. To provide radial support to a blood vessel, such as one that has been widened by a percutaneous transluminal coronary angioplasty, commonly referred to as “angioplasty,” “PTA” or “PTCA”, a stent may be implanted in conjunction with the procedure. Under this procedure, the stent may be collapsed to an insertion diameter and inserted into the vasculature at a site remote from the diseased vessel. The stent may then be delivered to the desired treatment site within the affected vessel and deployed, by self-expansion or radial expansion, to its desired diameter for treatment.
Recently, flexible prosthetic valves supported by stent structures that can be delivered percutaneously using a catheter-based delivery system have been developed for heart and venous valve replacement. These prosthetic valves may include either self-expanding or balloon-expandable stent structures with valve leaflets disposed within the interior of the stent structure. The prosthetic valve can be reduced in diameter, by being contained within a sheath component of a delivery catheter or by crimping onto a balloon of a dilatation catheter, and advanced through the venous or arterial vasculature. Once the prosthetic valve is positioned at the treatment site, for instance within an incompetent native or previously implanted prosthetic valve, the stent structure may be expanded to hold the prosthetic valve firmly in place. One embodiment of a prosthetic valve having a stent structure is disclosed in U.S. Pat. No. 5,957,949 to Leonhardt et al. entitled “Percutaneous Placement Valve Stent,” which is incorporated by reference herein in its entirety.
Valvular heart disease is any disease process involving one or more of the valves of the heart, i.e., the aortic and mitral valves on the left and the pulmonary and tricuspid valves on the right. Severe valve damage may be treated with a valve replacement, with aortic valves and severely damaged mitral valves being the most often replaced heart valves. Some patients present with more than one heart valve being damaged so that the patient may need a dual valve replacement requiring more than one heart valve to be repaired or replaced. Whereas the use of minimally invasive techniques may be preferred, such an approach may be difficult in a dual valve replacement as placement of the prosthetic mitral valve prior to or subsequent of placement of the prosthetic aortic valve may be extremely difficult due to the relative locations of the two native valves and/or the lack of space in the left ventricle, and/or the concern of having to cross the first deployed prosthetic valve with the second delivery system and prosthetic valve under certain circumstances. Moreover, when a prosthetic valve is percutaneously delivered to replace a stenotic or insufficient aortic or mitral valve, a fundamental concern is that the prosthesis be deployed as precisely as possible so as to assure proper functioning, to avoid paravalvular leakage and to minimize any negative impact on the adjacent heart valve, each of which becomes more difficult to achieve with a dual valve replacement performed using multiple prosthetic valves and delivery devices. Further, sufficient prosthetic mitral valve fixation against high systolic pressures is also particularly important as migration or movement of the mitral prosthetic device can potentially block the left ventricular outflow tract or inhibit native or replacement aortic valve function. As such patients who must have a dual valve replacement most often undergo open heart surgical replacement procedures to implant the prosthetic aortic and mitral valves or one of the valves goes untreated. Accordingly a need exists in the art for apparatus and methods that allow a clinician to perform a dual heart valve replacement in a minimally invasive manner.